Machine capable of operating as compressor and pump



P. AUGUST Dec. 31, 1963 Filed April s, 1962 United States Patent O 3,116,012 MACHINE CAPABLE F OPERATlNG AS CDMPRESSGR AND PUMP Pablo August, Directorio 130, Bernal, Buenos Aires, Argentina Filed Apr. 3, 1962, Ser. No. 184,303 12 Claims. (Cl. 230-207) The present invention relates to certain new and useful improvements in machines capable of operating as compressor and pump of the rotary type having a revolving displacer, and more particularly refers to a rotary cornpressor or pump with a cylindrical gyratory displacer or piston eccentrically arranged in a cylindrical casing and movably mounted on a central driving shaft with the interposition of an eccentric and of a suitable bearing, the gyratory motion of said displacer within the cylindrical casing being guided by a rib member of the displacer engaging a recess formed in the wall of said casing and acting at the same time as a means for separating the suction side from the pressure side of the compressor or pump, for which purpose said recess is situated between the inlet and outlet ports of said casing, the improvements provided by the invention in a rotary compressor or pump of the type referred to aiming at not only rendering its operation more ellicient, particularly in as far as this depends upon a good and reliable lubrication, but also at insuring an air-tight sealing eiect of said ribmember in its function of separating the suction side from the pressure side, simplifying at the same time its construction and arrangement of parts with regard to both the gyratory displacer and the recess of the compressor or pump casing, with the advantageous result that the machine improved according to the invention incorporates an irnportant technical progress.

The known compressors having a rotary displacer are disadvantageous in so far as there is provided between the suction side and the pressure side a spring-loaded blade member which requires relatively strong springs when the machine operating as a pump works at low speed and which is subject to wear and tear when the compressor works at high speed. Therefore, it is already proposed to use instead of said blade member a rib member forming part of the displacer or of the casing and engaging a recess formed respectively in the casing or in the displacer body. This arrangement, however, not only complicates the construction of the machine, but also fails in most of the cases in insuring the desired air-tight seal between the suction side and the pressure side. Further, in most of the known compressors, the lubrication of the machine constitutes a problem which has not yet been satisfactorily resolved.

The main object of the present invention is to provide a machine capable of operating as compressor and pump, comprising a cylindrical casing, a gyratory cylindrical hollow displacer eccentrically arranged in said casing and movably mounted with the interposition of an eccentric on a central shaft, a radially projecting blade member of said displacer extending into a recess formed in said casing between its inlet and outlet ports for preventing said displacer from rotating around its axis and for separating the suction side from the pressure side of the machine, a shoe member of elastic material provided on the foot portion of said blade member and an anchorage groove formed in said displacer body for resiliently anchoring said shoed foot portion of said blade member, pairs of mutually opposite guide means arranged in the side walls of said recess and in guide contact with said blade member for causing the latter to perform straight reciprocating movements and for enabling it to operate as a pump piston in said recess as pump chamber, and duct ICC means connecting said recess with a source of lubricating oil to provide in combination with said pump chamber and said pump piston a lubricating system for the machine.

In accordance with one characteristic feature of the invention, the said shoe member of elastic material on the foot portion of the said blade member is of such construction and arrangement that in spite of the slight oscillatory movements of the gyratory displacer, the blade member may act with straight reciprocating movements in the said recess of the machine casing as a pump piston of the lubricating system.

According to another characteristic feature of the invention, the said shoe member of elastic material such as rubber, a suitable synthetic material and the like, which surrounds a thickened foot portion of the said blade member is of such arrangement and thickness that it allows for a simple insertion under pressure of the blade foot into a groove-like recess of preferably circular cross section of the displacer body and for the slight oscillatory of the gyratory displacer through an angle of about 5 to 6, with the advantageous result that, on the one hand, the blade member may be readily xed in place and the displacer as an entirely cylindrical body may be easily machined and that, on the other hand, said blade member may execute in the recess of the casing straight reciprocating movements which not only insure its correct operation as a pump piston, but also permits the same to be perfectly guided by several pairs of mutually opposite guide means in sealing contact therewith and this without generating practically any friction heat due to the aforementioned lubricating system.

The said blade member which according to the invention forms part of a lubricating system produces a circulating air current which by way of corresponding ducts is caused to pass over a source of lubricating oil, to take up very small quantities of this oil and to supply an oilcarrying air current to the said blade member and other parts for their lubrication, the arrangement of said ducts being such that the circulation of the oil-carrying air current proceeds in the desired direction.

In order to maintain the oil supply within the desired small limited quantities, the transfer of the lubricating oil from a suitable oil receptacle conveniently provided in the base or support of the machine to the said air current is preferably effected by means of a Wick, a nozzle or the like.

Thus the invention provides for a perfect lubrication of the machine. In view of the fact that after lubricating the said blade member certain minor part of the oilcarrying air current enters the chamber formed between the displacer body and the inner wall of the casing, the surfaces of these parts are also provided with a thin oil film which due to its natural adhesion to said surfaces does not contaminate the air or gas compressed by the compressor as could be proved by practical tests.

The compressor casing is as usually provided with cooling ribs. These ribs according to an additional feature of the invention are so arranged that they do not interfere with the centering or guide means for centering the end walls of the compressor casing, with the advantageous result that said guide means, Without conllicting with the cooling ribs, may be surely lixed and provided at symmetrically distributed points conveniently situated on a circle passing through the outer end edges of that casing portion which forms the recess to be engaged by the afore-mentioned blade member, and in this manner construction and assembling of the compressor are considerably simplified.

The accompanying drawing illustrates by way of example a preferred embodiment of the invention in a partly sectional view of the compressor without its front end wall.

Having reference to the accompanying drawings, the compressor or pump according to the invention comprises a cylindrical casing 1 provided with an inlet port 2 and with an outlet port 3, a central shaft 4, an eccentric 5 iixedly mounted on said shaft, a bearing 6 loosely arranged on said eccentric, and a cylindrical hollow displacer 7 movably carried by said bearing. The diameter of the displacer body 7 is such that its circumference does not contact the inner casing wall, but that a very small distance of a few hundredths of a millimeter is always left between these parts. Further, in an already known arrangement, the displacer 7 is prevented from rotating around its axis, but is caused to execute a gyratory motion within the casing 1.

This gyratory motion of the displacer 7 is produced, on the one hand, by the eccentric 5 and, on the other hand, by a guide blade 8 in co-operation with a guide recess 9 formed in an outwardly projecting extension of the casing 1.

This arrangement is essentially known. However, as distinguished from the known compressors wherein the guide blade forms an integral part of the displacer body and moves oscillatorily in a recess of the compressor casing or vice-versa is rigidly secured to the latter and engages a recess or" the displacer body, in accordance with the present invention, the guide blade S is movably and resiliently anchored in the displacer body '7 and is guided in the recess of the casing 1 so as to execute straight reciprocating movements and to act as a pump piston in a pneumatic lubricating system.

For this purpose, according to the invention the guide blade 3 is provided with a thickened foot portion 11 embedded in a shoe of elastic material such as rubber, a suitable synthetic material and the like. The elastic shoe 12 has suiiicient wall thickness to be somewhat compressed and to permit the insertion under pressure of the blade foot 11 into a corresponding groove-like recess 13 of the displacer body 7 and the anchorage of the blade 8 in said recess. Thus the displacer body as such has an entirely circular circumference and as the groove 13 has a preferably circular cross section, the displacer 7 may be readily machined.

ln addition hereto the wall thickness of the shoe 12 is such that it may suffer certain compression and deformation and that it yieldingly allows that blade member 8 to maintain its normal direction in spite of the slight oscillatory movements of the displacer through an angle of about 5 to 6. On the other hand, the elastic shoe 12 in spite of its compression and deformation always maintains an air-tight seal between the displacer body '7 and the blade member 8. Finally the arrangement of the blade 8 and its anchorage in the displacer body 7 as above described are advantageous insofar as, if necessary, the blade member may be readily interchanged at any time.

The guide blade 8 in turn is guided in the recess 9 according to the invention by at least two pairs of opposite loose rollers 14, 14 embedded in the side walls 1S of the recess 9 and so arranged that they slightly project from the surfaces of said side walls and maintain a permanent contact with the side walls of the blade member 8, thus the arrangement being such that this blade is compelled to execute straight reciprocating movements. In view of the fact that the two pairs ot guide rollers 14, 14 insure a sealing effect on both sides of the blade member d, the latter due to its reciprocating movements is in perfect condition to act as a pump piston and to produce a circulation of air in a lubricating system. The rollers 14, 14 are rotatively mounted in the end walls of the casing 1 in any suitable known manner. They are conveniently made of hard metal so that the casing 1, may be advantageously made of light metal.

in any case, the casing 1 is as usually provided with cooling ribs 1S. These ribs, however, according to the invention are so arranged that they do not complicate the provision of the required guide means for centering the end walls of the casing with regard to its cylindrical body 1. For this purpose the ribs 15 are either shorter in radial extension or are slightly withdrawn from the ends of the cylindrical casing body 1. In such arrangement the cool ing ribs do not interfere with the centering or guide means indicated at 16 and these means may be provided at symmetrically distributed points situated on a circle comprising the outer end edges of the casing portion 10.

The casing 1 includes a base or support 17 which in a preferred embodiment of the invention is made hollow yand contains a removable oil receptacle `18. A wick '19 in this receptacle extends through a cover plate 2G into a duct 21 provided in the casing material above said receptacle and conveniently formed by a perforation eX- tending longitudinally through the base portion 17. Instead of the wick '19 a nozzle may be arranged in the cover plate 29 so as to project into the duct 21.

`One end of this duct 21 is connected by means of a pipe preferably arranged outside the casing 1 and indicated at 22 and by means of an interchangeable nozzle 23 conveniently constructed as a Venturi tube with the interior of the recess 9 above the blade 8, whereas the opposite end of the duct 21 is connected by way of a pipe or duct 26 which communicates at the upper end thereof by a short duct .-27 with at least one duct 24, which by way of orifices 25 establishes the communication with the interior of the recess 9 between the rollers 14, 14; 14', 14. Conveniently two ducts 24 are provided, one on each side of the recess 9 and the drawing shows tWo ducts 27 between the upper end of duct 26 and the ducts 24, respectively.

rThe cross sectional area of the nozzle 23 has to be always larger than that of the orifices 25 in order to insure that the circulation of air produced by the piston blade S proceeds in the correct direction i.e. from the recess 9 above said blade by way of the nozzle 23, pipe 22, duct 21, ducts 2.4, and orifices 25 into the 'recess 9 between the rollers 14, 14, 14', 14 and not in opposite direction.

During the operation of the compressor the reciprocating movements of the blade 8 acting as a pump piston in the pump chamber 9 produces a circulating current of air which while passing through the duct 21 receives from the wick 19 a small quantity of lubricating oil and delivers this oil to the recess 9' between the rollers 14, 14', This oil lubricates at irst instance the blade surfaces and said rollers and part of the oil-carrying air enters the cylindrical casing 1 with the advantageous result that the inner walls of this casing as well as the outer surfaces of the displacer body are also provided with `a very thin iilm of lubricating oil. Due to its natural adhesion to said surfaces, the oil iilm proved to be unable to contaminate the air or gas compressed by the compressor. Corresponding tests proved that after a passage of 15,000 liters of compressed air the oil consumption amounted to but l g. of oil and that in spite of this practically oil-free compressed air the displacer and the inner walls of the casing were perfectly coated with a thin oil lm. The maintenance of this lubricating lm is the result of the circulation of the oil-carrying air current and of the eflicient control of the limited quantity of oil supplied to the air current as provided by the lubricating system according to the invention.

What I claim is:

l. A machine capable of operating as compressor and pump, comprising a cylindrical casing formed with an inlet port and an outlet port and an elongated recess extending between said ports in substantially radial direction from the inner toward the outer surface of said casing and being closed at the outer end thereof, a gyratory cylindrical hollow displacer movably mounted by interposition of an eccentric on a central driving shaft in said casing, a blade member radially projecting from said displacer into said recess Iformed in said casing, said blade member and said recess having substantially parallel side IWalls, a shoe member of elastic material of substantial thickness provided on a thickened foot portion of said blade member and a corresponding anchorage groove formed in the displacer body for movably and yieldingly anchoring said blade member, the cross sectional area of said groove being slightly smaller than that defined by the outer surface of said shoe member, at least two pairs of mutually opposite guide means of loose rollers slightly protruding from the side walls of said recess and being in permanent contact with the side walls of said blade member, an outlet opening provided in the closed outer end of said recess and inlet openings provided in the side walls of said recess l-between said rollers, a source of lubricating oil, and duct means for connecting said outlet and inlet openings of said recess with said source of lubricating oil to provide in combination with said blade member as a pump piston and with said recess as a pump chamber a pneumatic lubricating system.

2. A machine capable of operating as compressor and pump, comprising a cylindrical casing formed with an inlet port and an outlet port and an elongated recess extending between said ports in substantially radial casing `and being closed at the outer end thereof, a gyratory' hollow cylindrical displacer movably mounted by interposition of an eccentric on a central driving shaft in said casing, a blade member projecting from said displacer into said recess formed in said casing, said blade member and said recess having substantially parallel side walls, a shoe member of elastic material of Substantial thickness provided on a thickened foot portion of said |blade member and a corresponding anchorage groove formed in the displacer body for movably and yieldingly anchoring said blade member, the cross sectional area of said groove being slightly smaller than that defined by the outer surface of said shoe member, at least two pairs of mutually opposite loose guide rollers slightly protruding from the side walls of said recess and being in permanent contact with the side walls of said blade member, an air outlet provided in the closed outer end of said recess and air inlets provided in the side walls of said recess between said rollers, the cross sectional area of said air inlets being smaller than that of said air outlet, oil-supply means including a receptacle of lubricating oil, and duct means connecting said air outlet and air inlets with said oil-supply means to provide in combination with said blade member as a pump piston and with said recess as a pump chamber a pneumatic lubricating system.

3. A machine capable of operating as compressor and pump as set forth in claim 2, wherein said oil receptacle is provided with a over plate and said oil-supply means consists of a wick extending through an opening in said cover plate into said duct means connected with said air outlet and said air inlets of said recess.

4. A machine capable of operating as compressor and pump `as set forth in claim 2, wherein that said oil receptacle is provided with a cover plate and that said oil-supply means consists of at least one nozzle in said cover plate connecting said receptacle with said duct means connected with said air outlet and said -air inlets of said recess.

5. A machine capable of operating as compressor and pump as set forth in claim 2, wherein said oil receptacle is arranged in a hollow base portion of the machine.

`6. A machine capable of operating as compressor and pump as `set forth in claim 2, wherein said air outlet of said recess comprises an interchangeable nozzle.

7. In combination with a machine capable of operating as compressor and pump and including a cylindrical casing formed with an inlet and an outlet port and an elongated recess extending in substantially radial `direction between said ports from the inner towards the outer surface of said cylindrical casing and being closed at the outer end thereof, a central shaft extending through said cylindrical casing, an eccentric mounted on said shaft for rotation therewith, a cylindrical hollow displacer arranged around said eccentric, and a baled member radially projecting from said displacer into said recess and having a free end spaced from said closed outer end of said recess, a lubricating system comprising air duct means having an outlet opening at one end thereof at said closed end of said recess and communicating through said outlet opening with the interior of said recess and having an inlet opening at the other end thereof communicating with the interior of said recess at a portion of the latter spaced further from said closed end than said free end of said blade member, said air duct means Ibeing formed with an opening between said ends; and lubricating oil supply means extending through said opening into said air duct means, whereby during rotation of said shaft said blade member will be reciprocated in said recess and expel air located in said recess above said free end of said blade member through said outlet opening to provide for an air stream through said air duct means, which in passing over said oil supply means will become saturated with oil vapor so that an oil carrying air stream will enter through said inlet opening into said recess to lubricate said blade member as well as the inner surface of said casing rand the outer surface of said displacer.

8. In a machine as defined in claim 7, in which said outlet opening has a greater cross sectional area than said inlet opening.

9. In a machine as defined in claim 7 in which said outlet -opening includes an interchangeable nozzle.

10. 'In a machine as defined in claim 7 in which said oil supply means includes a wick extending with one end thereof through said opening formed in said air duct means and a lubricating oil receptacle into which the other end of said wick extends.

l1. In a machine as defined in claim 7 and including a nozzle located in said opening formed in said air duct means between the ends thereof.

12. In a machine as defined in claim 7, in which said casing includes a base portion forming a chamber and in which said lubricating oil supply means includes an oil receptacle located in said chamber and passage means communicating with said receptacle and said opening formed in said air duct means between the ends thereof.

References Cited in the file of this patent UNITED STATES PATENTS 1,876,370 Weber Sept. 6, 1932. 2,276,355 Van Ranst Mar. 17, 1942 2,422,972 Knowles June 24, 1947 2,460,617 Balogh Feb. 1, 1949 2,995,292 Fleming Aug. 8, 19611 FOREIGN PATENTS 198,133 Austria Nov. 15, 1957 491,585 France June 7, 1919 1,116,975 Germany Nov. 9, 19611 257,103 Italy Oct. 2, 1926 

7. IN COMBINATION WITH A MACHINE CAPABLE OF OPERATING AS COMPRESSOR AND PUMP AND INCLUDING A CYLINDRICAL CASING FORMED WITH AN INLET AND AN OUTLET PORT AND AN ELONGATED RECESS EXTENDING IN SUBSTANTIALLY RADIAL DIRECTION BETWEEN SAID PORTS FROM THE INNER TOWARDS THE OUTER SURFACE OF SAID CYLINDRICAL CASING AND BEING CLOSED AT THE OUTER END THEREOF, A CENTRAL SHAFT EXTENDING THROUGH SAID CYLINDRICAL CASING, AN ECCENTRIC MOUNTED ON SAID SHAFT FOR ROTATION THEREWITH, A CYLINDRICAL HOLLOW DISPLACER ARRANGED AROUND SAID ECCENTRIC, AND A BALED MEMBER RADIALLY PROJECTING FROM SAID DISPLACER INTO SAID RECESS AND HAVING A FREE END SPACED FROM SAID CLOSED OUTER END OF SAID RECESS, A LUBRICATING SYSTEM COMPRISING AIR DUCT MEANS HAVING AN OUTLET OPENING AT ONE END THEREOF AT SAID CLOSED END OF SAID RECESS AND COMMUNICATING THROUGH SAID OUTLET OPENING WITH THE INTERIOR OF SAID RECESS AND HAVING AN INLET OPENING AT THE OTHER END THEREOF COMMUNICATING WITH THE INTERIOR OF SAID RECESS AT A PORTION OF THE LATTER SPACED FURTHER FROM SAID CLOSED END THAN SAID FREE END OF SAID BLADE MEMBER, 